Yoda, I have the exact some problem and I agree with Nexus in that it's just psychological....still, it's a pain in the arse. A while ago i decided to give up smoking for a bit and my doctor gave me benzos to sleep and for the cravings and my advice is that that shit is much, much worse than they make it out to be. I had a much harder time getting off them than the pot (I had to start smoking pot again to do it...lol) so my advice is, don't go there. Besides if you take a benzo or sleeping pill etc, although you might get 10 hours sleep, you'll still feel tierd the next day.
If I do happen to run out of weed and know i won't be able to sleep that night, i just get a bottle of red and make merry until I'm drunk enough to pass out in bed..
but i think the healthiest solution is to have a good book to read in bed and read until your eyes start closing...